Dyestuffs



Patented 23, 19 4 1 I v UNITED STATE sv PATENT oFFIC-E DYESTUFFS Talfryn James and na'viii Charles Forsht, 'Lock Haven, Pa assignors to American Aniline Products, Inc., New York, N. Y., a corporation of New York NoDrawingt Application June 27, 1935,

Serial No. 216,066

1 Claim.

. This invention relates to the manufacture of dyestuffs and their application to artificial silks, and it is particularly concerned with dyeing cellulose acetate silks with dyestuils whichyield a color ranging from a jet black to a green blue. The invention provides a novel dyestufi for such silks which is of'peculiar advantage in' carry ing out dyeing operations.

In dyeing cellulose acetate material with dyes of this type, it is diflicult rapidlyto distribute and secure the full color throughout'the fibres of the yarn, by reason of the slow manner in which the fibres-absorb such dyes. This is particularly true of heavy fabrics, thefibres of which are reached and penetrated withextreme difilculty.

The slowness with which dyeing operations of this typeare at present carried out is a considerable handicap to commercial'practice. Pres.

. ent day requirements call for speed'in dyeing in order to meet demands for immediate deliveries caused by rapid style changes.

Moreover, relatively high'cohcentratiOns of to drive the dye into the fibre. After the dyeing is complete, considerable quantities of unabsorbed dyestuffs are left in the bath, which is wholly wasted unless the dyer has additional orders for that particular colored yarn in which case. he

N:NON Reduce canon As a specific example of one way in which we 7 may prepare a dyestufi, we dissolve 1 mol of para nitroaniline in an excess of concentrated hydrochloric or sulphuric'acid and cool the solution to a temperature below C. We then stir in a solution 'of,sodium nitrite sufficient to diazotize completely the para nitroaniline. This diazotized compound is intermixed with an aqueous solution of phenyl diethanolamine-at any temperature within the approximate range of -10 to +40 0., either in. a neutral or alkaline state, by the addition of an alkaline compound such as caustic soda, sodium acetate, sodium phosphate,-0r" sodium carbon-ate. The dyestuff thus formed may be v filtered and reduced with aconcentrated solution ofa sulphide such as sodium sulphide, or the reduction may be carried out in-the coupled suspension without filtration. The final dyestufl' is then filtered, washed, driedand pulverized.

A The manner in which the reaction, proceeds 'will 'be observed from the following structural This product dyes cellulose acetatefilaments with great rapidity and permits increased procan use the partially spent bath only by fortifying it with additional dyestufl.

Objects of the invention are to overcome these difliculties and to provide a color which will be rapidly absorbed by the material to bedyed and which will be almost completely absorbed there Ill in, and thus to speed up production materially and at the same time efiect large economies by avoidingwaste of dye bath ends.

In general, the invention consists. in diazotizing aromatic nitro amines and their substituted,

derivatives, suchas 'chlor, or brome, etc., and.

coupling the diam) compound thus prepared with mono hydroxy ethyl, d1 hydroxy ethyl, mono hydroxy ethyl ethylderivatives of aromatic amines or their substituted derivatives. Thecompoundto ally contains an aliphatic radical such as methyl, ethyl or a higher straight chain compound.

' be coupled with the said diazo compound gener- I, I

' either hydrochloric acid or .duction in machine or jig dyeing treatments.

Furthermore, the acetate fibres take up the dye so well that'the dye bath isexhausted practically completely, thereby eliminating waste in the spent dye bath.

The novel dyestufi is also of advantage in the dyeing process which generally proceeds .by adding the required weight of dyestuff to a solution of soap, alkali, and a dispersing agent such as Turkey red oil. This suspension is brought to the boil, cooled with cold water'to a temperature generally below 70 C. The material to be dyed is entered into thebath alter-it been wetted out. The temperature 0! the dyejbath is raised to about '15 8'0 C and the dyeing permitted to proceed until the required depth of coloris obtained, or the dye bath" exhausted. The material is then withdrawn, well, washed-with water and immersed in a bath containing sodium nitrite, to which is then added an acid, ingeneral practice ordinary temperature.

"' 51" canon v CsH40H p-amindbenzol-azo-dihydroxyethylauflinc V sulphuric acid, at

- thirty minutes.

The material is allowed to remain in this bath {or about twenty minutes, after which it is taken :=ouq,-iwe11 washed and the color'developed by immersing the 'material'at a temperature of about 35 C. in a bath made up of beta hydroxy naphthoic acid, or its derivatives," dissolved'in the required amount'of alkali such as caustic soda, and

- dried.

We have found that in the development of the color as above outlined by beta hydroxy naphthoic acid or its derivatives, theparticul'ar dyelstuflf of the, present invention reacts peculiarly to give varying shades of color, varying from a green blue to a jet black, depending solely on the amount of dyestutf available for the developing reaction. This is not true with ordinary black dyes, for although there may be more than one compound formed during the developing reaction, only one shade of color is produced thereby. Accordingly, in addition to the advantages of rapid and eflicient dyeing, we obtain the-advantage that we can greatly increase the range of color obtainable by this single dyestufl -simply by varying the amount thereof available for reaction with the beta hydroxy naphthoi'c' acid solution;

As an example of the way in which these diI- ferent results are accomplished, we take four percent. of para amino benzol azo-dihydroxyethylaniline, calculated on theweight oi thematerial to be treated, and follow out; the dyeing procedure outlined above until the, developing step is reached. a We then treat the dye-impregnated material with a weight of beta 'hydroxy naphthoic acid calculated as one percent. of the weight of the material treafiad. Thecolor develops into agreen blue. If, however, we use 10% of black dye and 1% of beta hydroxy naphthoic acid, we obtain a Jet black.

Having thus described our invention, what we claim is:

The process of treating cellulose acetate which comprises applying to said material para-amino benzol-azo-dihydroxyethyl-aniline in an amount of from 4% to 10% by weight of the acetate,

then diazotizing the dyestufi upon the material and coupling. thereon from a solution beta-hydroxynaphthoic acid, the amount of the coupling 

